1. Field of Disclosure
Aspects and embodiments of the present disclosure are directed to spectrometry systems and for apparatus and methods for delivering dopants to same.
2. Discussion of Related Art
Ion mobility spectrometers (IMS) and ion trap mobility spectrometers (ITMS) are used to detect and identify trace amounts of airborne chemicals. These types of spectrometers are sometimes employed to detect explosives or narcotics Ammonia and dichloromethane (DCM) are used as dopants that enable the transport of sampled materials within an IMS or ITMS spectrometer. These dopants are used to accept a transfer of charge created during ionization of a carrier gas used to carry a sample through the spectrometer. Ionization of the carrier gas is thus reduced, reducing the amount of spectrometer detector readings that might otherwise occur due to ionized carrier gas and increasing the signal to noise ratio of the spectrometer. A dopant may be introduced to a carrier gas by flowing the carrier gas around a permeation tube which releases a controlled concentration of a dopant into the carrier gas. In the current state of the art, a spectrometer uses two separate permeation tubes to convey the ammonia gas (positive ion dopant) and DCM (negative ion dopant) inside the spectrometer.